This invention relates to a process for preparing a gut glucagon antigen.
In this specification, abbreviations for various amino acids, peptides, protective groups, active groups, etc. are given by following the rules of IUPAC or IUB or by using conventional symbols, examples of which are shown below. And, where amino acids can include optical isomers, they are intended to indicate L-enantiomers unless otherwise specified.
Arg: arginine PA1 Trp: tryptophane PA1 Asn: asparagine PA1 Asp: aspartic acid PA1 Thr: threonine PA1 Ser: serine PA1 Glu: glutamic acid PA1 Gln: glutamine PA1 Ala: alanine PA1 Val: valine PA1 Met: methionine PA1 Leu: leucine PA1 Phe: phenylalanine PA1 Lys: lysine PA1 Tyr: tyrosine PA1 Ile: isoleucine PA1 Cys: cysteine ##STR1## Gly: glycine His: histidine PA1 Pro: proline PA1 Z: carbobenzoxy group PA1 Su: succinimido group PA1 Tos: p-toluenesulfonyl group PA1 Boc: tert-butoxycarbonyl group
Gut glucagon is a hormone playing an important role in sugar absorption metabolism. Assay of gut glucagon enables one to diagnose various pathological states gut glucagon takes part in, such as diabetes mellitus or gut cancer, and diagnose diseases such as gut diseases (e.g., diarrhoea, constipation, etc.), duodendal ulcer, carcinoid, gut glucagonoma, etc. Thus, assay of gut glucagon is increasingly noted in the field of diagnosis, pathology, physiology, etc. Gut glucagon is assayed by a method such as a radioimmunoassay method (RIA method) using an antibody (antiserum) which reacts with gut glucagon. As the antibody capable of reacting with gut glucagon, there has so far been known antibody R-64 prepared by Ravazzola et al [see Endocrinology, vol. 105, No. 2, pp. 499-508 (1979)]. However, such antibody does not have a specificity to gut glucagon.